In the transition from 3G to 4G, the idea of software upgradeability really took hold in the macro RAN. However, the proportion of the time and cost of a major upgrade that really could be moved from physical processes to code updates remained limited, and projects to upgrade or replace networks were still long, expensive and heavy on labor. In the transition to 5G, in which networks are inherently more software-based, the software upgrade is becoming a more meaningful term. Of course, antennas still have to be mounted on towers and fibers run for backhaul, but many of the 4G radios installed in recent years are 5G-ready, and even some physical processes are becoming more streamlined and automated, as operators look forward to innovations like drones installing antennas.
Nokia has released software for the first time, which can update most of its legacy 4G radio units to 5G. This will be important as operators – which initially deployed 5G mainly in unpaired TDD spectrum bands such as 3.5 GHz – start to deploy in paired FDD bands, some refarmed from 3G or 4G.
In particular, it will help operators to extend 5G coverage quickly and cost-effectively by using low band FDD spectrum, either through refarming or dynamic spectrum sharing (DSS), in which 4G and 5G can both use the same spectrum on a flexible basis. Uplink signalling, in particular, can be moved to the low FDD band, leaving the higher capacity TDD spectrum to be optimized for fast downlink.
“More than 80% of Nokia’s Flexi and AirScale FDD installed base is upgradeable to 5G via software,” said Sandro Tavares, global head of mobile networks marketing at Nokia. He said 359 LTE operators have deployed Nokia FDD radios that can be upgraded to 5G with the new software, and he expects at least one million of these radios to be software-updated in the near future, 3.1m by the end of this year, and over 5m in 2021.
This innovation should reduce the time and cost to upgrade to 5G, and is clearly a strong play by Nokia to keep operators loyal even when its 5G business has suffered technical and performance setbacks that have threatened to undermine confidence in its solutions. Earlier this month, for instance, it was reported that Verizon was replacing Nokia 5G base stations with Samsung, stories that both companies denied, but were given a fair dose of credence because of the Finnish firm’s current uncertain state.
Existing users can now start to upgrade their 4G base stations without incurring significant additional cost, while the capability should also be attractive to operators which are expanding their 4G networks, and planning 5G upgrades in the future. Ericsson already offers software upgradeability in its 4G/5G Ericsson Radio System (ERS), and this 5G readiness was credited with the company gaining share in several major markets, including China, just ahead of commercial 5G roll-outs.
Tavares said: “Each band of the 4G and 5G spectrum is defined for either FDD or TDD, so the key for this announcement is to make sure that we can refarm 4G FDD spectrum into 5G in the most efficient way”, while reducing the need for site visits, tower climbing, and permits. By cutting down on these activities, software upgradeability saves operators “tens of billions” of dollars, he argued.
Another point is that the leaps in performance that are achieved with new hardware are diminishing, because so much of a 5G network’s intelligence and efficiency will be a result of software – virtualized functions, software-defined networking and flexible allocation of resources through slicing. So the trade-offs of only updating the software, while hanging onto the same hardware for longer, are reducing, and no longer justify the replacement of equipment which is still functioning and has not yet been fully depreciated.
It seems some senior Nokia managers are only recent converts to this view, with some clinging to the old world in which significant differentiation came from hardware engineering. Although Nokia has previously promised 5G software upgrades, they have been far less central to its strategy than to Ericsson’s. And last year, outgoing CEO Rajeev Suri told analysts that “software-only upgrades are meaningless, unless your hardware has the right capacity”.
Of course, Nokia’s other big bid for operator attention lies in its strong support for O-RAN, as seen in its recent launch of a whole portfolio of 5G vRAN and O-RAN networks. The full suite of interfaces will be supported in 2021.
Tommi Uitto, president of mobile networks, said in an interview that Nokia had already won at least one commercial O-RAN deal. “As the specifications and this standard mature then of course over the next couple of years we will see more and more of this. So, it takes a couple of years to get to where we want to be in open RAN,” he said.
He agrees with many of Nokia’s major customers that O-RAN still has performance and interoperability challenges, but believes the next two years will see the industry “get to the dream of open RAN”. He added: “It was the very premise of the original GSM technology that there would be open interfaces between different network functions in order to drive scale, interoperability, choice, global technology and global roaming. We believe that the time has come to try and make it happen in radio technology.”